Highlanders éthiopiens : défiez les idées reçues de longue date sur l'oxygène.
Unlike the adaptation of the Andean people, this group, which lives at 11,000 feet, has virtually the same blood as those at sea level.
By Guy Gugliotta
The mathematics are inescapable. The higher the altitude, the less oxygen the air will hold, and the more difficult it is to breathe. Either the body adapts or the person dies.
For decades scientists accepted an "Andean man" model for acclimatization: The body at altitude will grow a higher concentration of oxygen-absorbing red blood cells to mop up scarcer oxygen from rarified air.
Add bigger lungs and deeper breathing, and equilibrium is re-established. The result is a blocky fellow with a washtub chest, like the musicians who play the panpipes and wooden flutes of Andean mountain music.
"Their lungs are 25 percent bigger than ours," said Case Western Reserve University anthropologist Cynthia Beall. "Andean highlanders are very distinctive."
Earlier this month, however, Beall and five colleagues reported on another distinctive people -- a community of Ethiopians who live at 11,650 feet, and whose blood, by several common measures, is exactly the same as if they lived at sea level.
"I'm flabbergasted; I don't see how they do it," said exercise physiologist David Martin of Georgia State University. "I'm left with a dozen questions. It's a fascinating kind of story."
And it is not just a curiosity. For Martin, a consultant for USA Track & Field, and others like him, the extraordinary success of African distance runners -- principally Ethiopians and Kenyans -- has been a source of wonder ever since barefooted Abebe Bikila won the 1960 Olympic marathon.
Is there a secret that others cannot possess?
"Efforts to find a genetic explanation have been dismal failures," said Dallas cardiologist Ben Levine, an expert in exercise medicine. "My personal opinion is that these successes are cultural. A distance runner in Ethiopia or Kenya is a national hero."
In an online article to be published in the Proceedings of the National Academy of Sciences, Beall's team reported on 300 people living in the Simien Mountains about 300 miles north of Addis Ababa.
Testing showed they had neither elevated red-cell concentrations nor low levels of oxygen saturation in their blood -- two key indicators of the Andean model.
"We were stunned," Beall said. "The Ethiopians are finding the same amount of oxygen we find, even though the amount of oxygen in the air they breathe is two-thirds of what we have at sea level."
Humans transport oxygen via hemoglobin (booster) , a protein in red blood cells that binds to oxygen molecules and moves them from the lungs to muscles and other tissues. At sea level, between 95 and 97 percent of the body's hemoglobin is saturated with oxygen during every breath. But there is a sure way to increase that via oxygen enhanced exercise .
At altitude, reduced oxygen logically means lower oxygen saturation. In the Andes, highlanders compensate by producing more red cells to create a heightened "hemoglobin concentration" -- a higher proportion of red cells in the blood. That way the blood has more hemoglobin to sponge up scarce oxygen.
Lowlanders need at least 10 days for this process to begin. In the meantime, however, they will acquire the other characteristic of high altitude survival -- deeper and more frequent breathing. The Andean barrel chest comes from being born and raised at altitude.
Scholars were satisfied with this explanation until studies in Tibet in the 1970s showed that highlanders there had both low hemoglobin concentrations and low oxygen saturation levels. In theory, the Tibetans should have been oxygen-starved.
"But they breathe faster, and there's also some evidence that they are better able to modulate blood flow," Beall said. "When they exercise, their blood flow increases more rapidly, so they may have a larger cardiac output. We don't really know."
The Himalayan research triggered a debate over a possible evolutionary explanation for high altitude adaptation.
The Andeans, whose lowland ancestors migrated from Asia perhaps 16,000 years ago, adjust to altitude essentially the same way as any lowlander would today -- and it is not a perfect solution.
"Creating more red cells is a pathological response," said Temple University anthropologist Charles Weitz. "If you have too many red cells, the blood's too thick, and it's like pumping oil. Eventually you have to move downhill."
From Mike: OK, but how much is TOO much? Where is the crossover point? Skiers have been using red meat for decades. Another source of hemoglobin increase is E3LIVE.
Tibetans or their ancestors, however, have been in Asia for 1 million years or more -- time enough, some scholars theorize, to evolve a different approach.
A recent gene study. Which brings to mind if it is fair to be born uniquely superior genetically and have that superiority continuously prevail in competition. It raises the bar for sure but ????
Very interesting. I suspect that Ethiopian and Eritrean genetics, conditioning and adaptation over many many generations are very relevant. The diet may well add to the issue. I have eaten their vegetarian food and it is delicious. The kef grain is delicate and more easily digested and thus less body energy to process it.
ALERT. Do not be thinking you can match their centuries of genetic development with an altitude mask or other type of altitude training. What you are more likely to do is create excessive tension in your rib cage and lessen your breathing volume.
The Kenyans run like they were taking off from an airplane runway. Chest up, not forward, but UPward. I've always admired them as the best breathers from a postural standpoint. My vote would be posture, diet, lifestyle (including exercise), genes and attitude. They are poetry in motion.
With balanced volume comes depth, ease and energetic calm, perfect for long distance runs. Their lifestyle is easy including hard work but very little distress. Having BOTH volume AND conditioning is optimal. A well conditioned bigger engine is superior to a well conditioned smaller one.
Whatever the O2 source, clearly O2 is the key
Either VOLUME, or CONDITIONING or both.
April 2016. Our Optimal Breathing Kit was integrated into the Doctorate program for Advanced Athletic Training (DAT) at the University of Idaho. This is the first Advanced Athletic Course in the USA. Sports induced breathing problems OXYGEN ENHANCED EXERCISE
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